Receive information about the device that you are using. Properties such as Model, Operating System, Version, Id, and even the ability to generate a unique Id for your application based off of these properties.

sqlite-net is an open source, minimal library to allow .NET and Mono applications to store data in SQLite databases. It is written in C# 3.0 and is meant to be simply compiled in with your projects. It was first designed to work with MonoTouch on the iPhone, but should work in any other CLI...
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SharpSerializer is an open source XML and binary serializer for .NET.
With only one line of code it can serialize types like: multidimensional array, nested array, array-of-arrays, polymorphic object (where value is inherited from the property type), generic type, generic listing (i.e. dictionary,...
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A rich library of helpers, services, and base classes for new and
existing Windows UWP apps to maximize awesomeness and minimize boilerplate garbage.
This library has a companion Visual Studio Extension called "Template 10 Template Pack".